How does it feel?
Look for the finest quality green tea, perhaps a matcha blend, and in a cup pour on water just off the boil. The colour of the water will move from an immediate greenish-yellow to a darker yellow-brown. Do not add milk or whitener. After five minutes take a sip and note the familiar dry, refreshing taste, only subtly aromatic. If you take this in hot weather you will also feel the cooling effect of even a hot cup of green tea.
All around the world the actions of traditional medicines were understood by their immediate sensory impacts. Click on each of green tea’s key qualities below to learn more:
Green tea is bitter, astringent, light and drying and safe to take regularly over many years.
What can I use it for?
Green tea is a healthy and refreshing daily drink that can be a good replacement for coffee, and may be better tolerated than black tea. There is some suggestion that it can be a useful part of a weight-loss regime.
For health problems it may best be seen as a long term health and wellbeing measure rather than a quick fix. It can be considered as a preventative against heart and circulatory disease, late-onset diabetes, dementia and even cancer. It is probably best value if you have high cholesterol levels, high blood pressure, and/or raised BMI (body-mass index).
Into the heart of green tea
Green tea, particularly its key ‘EGCG’ and other catechin constituents, have extraordinary antioxidant properties in the laboratory (stronger than vitamin C or E). However these are artificial environments and the real impact of antioxidants after consumption, digestion and metabolism in humans has been heavily over-promoted. Nevertheless the catechins in green tea appear to optimize the body’s own antioxidant defences, including via the ‘Nrf2 pathway’. This is likely to explain many of the health benefits of regular green tea consumption, particularly in reducing low-level inflammatory conditions. A very interesting area of benefit is in cases of ‘neuroinflammation’: recent observations that many brain and nervous problems may involve inflammation. A role here could justify the use of green tea, for example in chronic fatigue syndromes and to help prevent dementia.
A key part of the benefits of green tea are linked to its observed effects on improving the health and integrity of the lining of the blood vessels, the endothelium. It is at this surface that almost all inflammatory processes commence and ‘endothelial dysfunction’ has been implicated in a wide range of inflammatory diseases, cardiovascular problems, dementia and diabetes. Endothelial stresses may even contribute to the effects of ageing on the brain and nervous system.
Closely linked to this endothelial impact are likely benefits of green tea in reducing insulin resistance and improving glucose and fat metabolism. Modern lifestyles have dramatically increased insulin activity in the body, notably as a consequence of high carbohydrate diets and reduced exercise. Higher insulin levels eventually lead to endothelial and other cells becoming ‘insulin resistant’ with consequent disrupted sugar management and more fat storing. This ‘metabolic syndrome’ is associated with the onset of type 2 diabetes and associated cardiovascular problems, increased dementia risks and other long-term health consequences, and is perhaps the dominant health issue in modern developed societies.
Green tea is also a moderate source of caffeine. Caffeine in this context enhances cognitive alertness and helps to overcome fatigue and lift mood.
Green tea has been an important part of Chinese, and later Japanese and Korean social life over almost two millennia. The earliest accounts of Tea Ceremonies come from China around 1200 years ago during the Tang Dynasty when the ritual of infusing and serving tea was part of a religious ceremony called cha dao or ‘The Way of the Tea’.
Outside China tea was brought to Europe in the 16th century and became popular in Britain, with black tea overtaking green tea to become its most popular drink during the 18th century. It was initially promoted through ‘tea houses’ as a tonic and health drink before becoming a popular beverage. The British East India Company introduced tea production, as well as tea consumption, to India, in order to compete with the Chinese monopoly on tea.
What practitioners say
All the evidence and traditional usage points to the benefits of green tea being from drinking it regularly as part of a healthy lifestyle. This beverage habit, rather than supplements or practitioner prescriptions, is probably the most practicable option too. However the evidence points to some benefits being seen in only a few weeks and practitioners are likely to recommend drinking more green tea for the following purposes.
Brain performance: consumption of green tea, preferably as a life-long habit, is particularly helpful to reduce the effects of ageing and illness on cognitive function, memory retention and and other performance. The L-theanine in green tea increases serotonin, dopamine and gamma-aminobutyric acid (GABA) in the brain, all of which significantly boost mood, indicating it also in anxiety and depression.
Metabolic: green tea is recommended where there is a slow or under-active metabolic rate associated with higher BMI (body-mass index), belt size and other indicators of ‘metabolic syndrome’ all of which may point to late-onset diabetes and fatty liver problems.
Cardiovascular: The EGCG’s present in green tea protect the integrity of the blood vessels, so regular consumption is useful in any cardiovascular problem.
Skin: it has traditionally been used in inflammatory skin conditions associated with hormonal imbalance.
Did you know?
Tea is the most commonly consumed beverage in the world after water, with total annual sales exceeding US$43 billion globally in 2015, more than $11 billion of which is accounted for by green tea.
Green tea consumption is extremely widespread and very safe in moderate quantities. There have been concerns about the safety of high-dose green tea extracts.
Traditional Ayurvedic characteristics are
- Rasa (taste) Bitter and astringent.
- Virya (action) Stimulating and cleansing.
- Vipaka (post-digestive effect) Stimulating and cooling.
- Guna (quality) Drying.
- Dosha strengthens vata and pitta, and reduces excessive kapha
- Dhatu (tissue) Cardiovascular.
- Srotas (channel) Cardiovascular, lymphatic, hepatic.
There is considerable evidence for the effects of long-term green tea intake in improving cognitive performance. In a major systematic review of the evidence, involving over 66,000 subjects, there were significant improvements in memory and cognition in those who drank one or more daily cups of green tea regularly.
Given the likely role of endothelial dysfunction in the origins of inflammatory processes, cardiovascular problems, and ageing, it is noteworthy that there are clinical studies that reinforce the laboratory observations that green tea does improve endothelial function, with wider benefits on the cardiovascular system.
It is also interesting to note that regular green tea consumption seems to help reduce associated problems of insulin resistance and disrupted glucose and fat metabolism. In a cross-sectional survey of almost five thousand healthy adults in China, between 1-30 cups of green tea per week was associated with lower rates of blood sugar impairment. In one systematic review involving almost two thousand subjects green tea was found significantly to lower fasting blood glucose levels. In another green tea was found significantly to improve measures linked to metabolic syndrome: to decrease weight, BMI (body-mass index), total and low density cholesterol, fat mass, and waist and hip circumference.
In a double-blind randomised controlled clinical trial of 60 individuals with raised cholesterol levels 600ml catechin-rich green and oolong tea taken daily for 12 weeks significantly reduced antioxidant enzymes and other measures of oxidative stress, with reductions also in body weight, fat levels and BMI. Markers of fatty liver levels were also improved. Green tea was seen in another systematic review of 600 patients with type 2 diabetes, to reduce C-reactive protein levels, one of the classic markers of inflammatory stress.
The suggested role of green tea in preventing cancer has been boosted by recent research into mechanisms of action of EGCG.
To see the references used in this summary check our downloadable Expert Herbal Reality Resource pdf
1-3 teaspoons dried leaf infused in hot (not boiling) water, one to three times a day.
Green tea has similar constituents to the fresh leaf:
- Flavanols up to 30% dry weight including catechins (epigallocatechin gallate (EGCG), epicatechin (EC), gallocatechin (GC), epigallocatechin (EGC), epicatechin gallate (ECG), and gallocatechin gallate (GCG)); also chlorogenic acid, coumarylquinic acid, theogallin (3-galloylquinic acid)
- Methylxanthines caffeine (2.5-4.5%), theobromine, theophylline (only traces)
- Amino acids incl. L- theanine (5-nethylglutamine)
According to the United States Department of Agriculture (USDA) brewed green tea contains an average of 126.6 mg total catechins and 77.8 mg EGCG per 100 ml, on the basis of 1 g leaf/100 mL infusion.
Black tea involves the oxidation of the catechins, enzymatically producing various condensation quinone compounds, including thearubigens, bisflavanols, theaflavins, epitheaflavic acids, which impart the characteristic taste and colour properties of black tea, as well as proanthocyanidins. Most of these compounds readily form complexes, including with caffeine. These complexes are erroneously given the name ‘tannins’: in fact there is no tannic acid in black tea.
The catechin EGCG translates its powerful antioxidant properties in the laboratory into real benefits by reducing inflammatory damage in the body.